1. Field of the Invention
The present invention relates to a detergent composition for use in non-aqueous cleaning. More particularly, the invention relates to a detergent composition for use in non-aqueous cleaning of clothes, such as dry cleaning.
2. Description of the Prior Art
One of the roles of a detergent used in dry cleaning is the solubilization of water. The purposes of the solubilization of water are to remove water-soluble stains from clothes into the water solubilized by the action of the detergent into a dry cleaning organic solvent (such as a petroleum type solvent, Perclene (tetrachloroethylene) or a fluorine type solvent) and to protect the clothes from shrinkage, deformation and color fading caused by water. Another purpose is to minimize the increase of the pressure of a filter for filtering the washing liquid by solubilizing water introduced with the clothes into the washing bath. It is logical that detergents for achieving the foregoing purposes should have a high water solubility, namely, a capacity of solubilizing a large quantity of water into an organic solvent.
As surface active agents of a detergent that can be used for achieving the foregoing purposes, there can be mentioned anionic surface active agents such as petroleum sulfonates, dialkylsulfosuccinic acid esters, long chain alkylbenzenesulfonic acid salts, non-ionic surface active agents such as polyoxyethylene nonylphenyl ethers, fatty acid sorbitan esters, fatty acid alkylolamides and polyoxyethylene alkyl ethers, and amphoteric surface active agents such as imidazoline-type alkylbetaines.
Petroleum sulfonates are obtained as by-products during the process of refining petroleum and they have heretofore been used frequently. However, because of process limitations, they are dark brown in color. Therefore, the use of such surface active agents is limited because there is a fear that the washed clothes will be colored by the surface active agent remaining in the clothes. Dialkylsulfosuccinic acid esters, which comprise one class of a limited number of surface active agents which are soluble in organic solvents, are frequently used in this field. However, the water solubilizing property thereof is very highly dependent on temperature and such an agent cannot be used alone. Various non-ionic surface active agents with optimum HLB values are also used in this field. However, since the temperature dependency of the water solubilizing property thereof also is high, they are used only in combination with other surface active agents. Among the long chain alkylbenzenesulfonic acid salts, the so-called hard-type (branched chain-type) alkylbenzenesulfonic acid salts are soluble in organic solvents, even if they are alkali metal salts, and they are used as non-aqueous detergents. However, because it is difficult to decompose them biologically, they will not be able to be used in the future. Alkali metal salts of linear alkylbenzenesulfonic acids having 10 to 16 carbon atoms in the alkyl group, which are used in large quantities as water-soluble detergents, are poorly soluble in organic solvents. Accordingly, these linear alkylbenzenesulfonic acids are used for non-aqueous cleaning in the form of their lower amine or lower alkanolamine salts. Propylamine, dipropylamine and butylamine are often used as the counter ion of these amine salts, but they have a low boiling point and are quite volatile, and they are inflammable and have a high toxicity. The use of these lower amine salts is not preferred in view of the difficulties of the preparation process and also in view of the properties of the resulting composition. Lower alkanolamine salts are still insufficient in their solubility in organic solvents, and they are poorly dissolved in petroleum-type solvents having a low solubility and therefore, they cannot be used conveniently.
It is a primary object of the present invention to provide a detergent composition having a high water solubilizing power, which can be prepared very easily and in which the foregoing disadvantages of the conventional detergents can be eliminated.